Bariatric surgery procedures, such as sleeve gastrectomy, the Rouen-Y gastric bypass (RYGB), and the biliopancreatic diversion (BPD), modify food intake and/or absorption within the gastrointestinal system to effect weight loss in obese patients. These procedures affect metabolic processes within the gastrointestinal system, by either short-circuiting certain natural pathways or creating different interaction between the consumed food, the digestive tract, its secretions and the neuro-hormonal system regulating food intake and metabolism. In recent years, there has been a growing clinical consensus that obese diabetic patients who undergo bariatric surgery see remarkable resolution of their Type-2 Diabetes Mellitus (T2DM) soon after the procedure. The remarkable resolution of diabetes after RYGB and BPD typically occurs too fast to be accounted for by weight loss alone, suggesting that there may be a direct impact on glucose homeostasis. The mechanism of this resolution of T2DM is not well understood, and it is quite likely that multiple mechanisms are involved.
One of the drawbacks of bariatric surgical procedures is that they require fairly invasive surgery with potentially serious complications and long patient recovery periods. In recent years, there is an increasing amount of ongoing effort to develop minimally invasive procedures to mimic the effects of bariatric surgery using minimally invasive procedures. One such procedure involves the use of gastrointestinal implants that modify transport and absorption of food and organ secretions. For example, U.S. Pat. No. 7,476,256 describes an implant having a tubular sleeve with an anchor having barbs. While these implants may be delivered endoscopically, the implants offer the physician limited flexibility and are not readily removable or replaceable, as the entire implant is subject to tissue in-growth after implantation. Moreover, stents with active fixation means, such as barbs that penetrate into the surrounding tissue, may potentially cause tissue necrosis and erosion of the implants through the tissue, which can lead to serious complications such as systemic infection. Also, due to the intermittent peristaltic motion within the digestive tract, implants such as stents have a tendency to migrate.